Cardiomyocytes lose their division potential at the time of birth and hence their regeneration is difficult. Therefore, recent interest has focused on replacement therapy wherein cardiomyocytes obtained by differentiation induction of cells having pluripotency (WO/2007/069666), such as embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells), are transplanted to a cardiac tissue that has been damaged due to myocardial infarction, myocarditis, aging or the like. Although many methods for differentiation induction of such pluripotent stem cells into cardiomyocytes have been reported (WO2007/002136, WO2009/118928 and Yan P, et al., Biochem Biophys Res Commun. 379:115-20 (2009)), it is necessary to enhance the purity of the cardiomyocytes by sorting or the like for using the induced cells in transplantation. Although, at present, CD166 (ALCM) (Rust W, et al., Regen Med. 4, 225-37 (2009)), N-cadherin (JP 2010-158206 A and Honda M, et al., Biochem Biophys Res Commun. 29, 351, 877-82 (2006)) and the like have been reported as surface markers for cardiomyocytes and/or cardiac progenitor cells, it is necessary to find more markers for enhancing the purity of cardiomyocytes.